Azure SQL Database has added more fault resilience to premium databases by taking advantage of availability zones in select regions. Provision your premium databases or premium elastic pools with multiple replicas deployed to different availability zones at no extra cost.
Zone redundant premium databases and elastic pools expands upon the automatic data and compute redundancy SQL Database currently provides for databases in the same region. The service is currently available in Central US, West Europe, and France Central, with additional regions to be added over time.
Learn more about zone redundant premium databases and elastic pools.
Source: Azure Roadmap